/*
* Copyright 2017 Async-IO.org
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
// This class was hightly inspired by its Cometd implementation
/*
* Copyright (c) 2010 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.atmosphere.cometd;
import org.atmosphere.cpr.HeaderConfig;
import org.cometd.bayeux.Channel;
import org.cometd.bayeux.Message;
import org.cometd.bayeux.server.ServerMessage;
import org.cometd.server.AbstractServerTransport;
import org.cometd.server.BayeuxServerImpl;
import org.cometd.server.ServerSessionImpl;
import org.cometd.server.transport.LongPollingTransport;
import org.eclipse.jetty.continuation.Continuation;
import org.eclipse.jetty.continuation.ContinuationListener;
import org.eclipse.jetty.continuation.ContinuationSupport;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.text.ParseException;
import java.util.List;
import java.util.Map;
public class WebSocketTransport extends LongPollingTransport {
private final Logger logger = LoggerFactory.getLogger(getClass());
public final static String PREFIX = "long-polling.ws";
public final static String NAME = "websocket";
public final static String MIME_TYPE_OPTION = "mimeType";
public final static String CALLBACK_PARAMETER_OPTION = "callbackParameter";
private String _mimeType = "text/javascript;charset=UTF-8";
private String _callbackParam = "jsonp";
private boolean _autoBatch = true;
private boolean _allowMultiSessionsNoBrowser = false;
private long _multiSessionInterval = 2000;
public WebSocketTransport(BayeuxServerImpl bayeux) {
super(bayeux, NAME);
setOptionPrefix(PREFIX);
}
/**
* @see org.cometd.server.transport.LongPollingTransport#isAlwaysFlushingAfterHandle()
*/
@Override
protected boolean isAlwaysFlushingAfterHandle() {
return true;
}
/**
* @see org.cometd.server.transport.JSONTransport#init()
*/
@Override
protected void init() {
super.init();
_callbackParam = getOption(CALLBACK_PARAMETER_OPTION, _callbackParam);
_mimeType = getOption(MIME_TYPE_OPTION, _mimeType);
}
@Override
public boolean accept(HttpServletRequest request) {
return request.getHeader(HeaderConfig.X_ATMOSPHERE_TRANSPORT) == HeaderConfig.WEBSOCKET_TRANSPORT;
}
@Override
public void handle(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
// Is this a resumed connect?
LongPollScheduler scheduler = (LongPollScheduler) request.getAttribute(LongPollScheduler.ATTRIBUTE);
if (scheduler == null) {
// No - process messages
// Remember if we start a batch
boolean batch = false;
// Don't know the session until first message or handshake response.
ServerSessionImpl session = null;
boolean connect = false;
try {
ServerMessage.Mutable[] messages = parseMessages(request);
if (messages == null)
return;
PrintWriter writer = null;
for (ServerMessage.Mutable message : messages) {
// Is this a connect?
connect = Channel.META_CONNECT.equals(message.getChannel());
// Get the session from the message
String client_id = message.getClientId();
if (session == null || client_id != null && !client_id.equals(session.getId())) {
session = (ServerSessionImpl) getBayeux().getSession(client_id);
if (_autoBatch && !batch && session != null && !connect && !message.isMeta()) {
// start a batch to group all resulting messages into a single response.
batch = true;
session.startBatch();
}
} else if (!session.isHandshook()) {
batch = false;
session = null;
}
if (connect && session != null) {
// cancel previous scheduler to cancel any prior waiting long poll
// this should also dec the browser ID
session.setScheduler(null);
}
boolean wasConnected = session != null && session.isConnected();
// Forward handling of the message.
// The actual reply is return from the call, but other messages may
// also be queued on the session.
ServerMessage.Mutable reply = bayeuxServerHandle(session, message);
// Do we have a reply ?
if (reply != null) {
if (session == null) {
// This must be a handshake, extract a session from the reply
session = (ServerSessionImpl) getBayeux().getSession(reply.getClientId());
// Get the user agent while we are at it, and add the browser ID cookie
if (session != null) {
String userAgent = request.getHeader("User-Agent");
session.setUserAgent(userAgent);
String browserId = findBrowserId(request);
if (browserId == null)
setBrowserId(request, response);
}
} else {
// Special handling for connect
if (connect) {
try {
writer = sendQueue(request, response, session, writer);
// If the writer is non null, we have already started sending a response, so we should not suspend
if (writer == null && reply.isSuccessful() && session.isQueueEmpty()) {
// Detect if we have multiple sessions from the same browser
// Note that CORS requests do not send cookies, so we need to handle them specially
// CORS requests always have the Origin header
String browserId = findBrowserId(request);
boolean allowSuspendConnect;
if (browserId != null)
allowSuspendConnect = incBrowserId(browserId);
else
allowSuspendConnect = _allowMultiSessionsNoBrowser;
if (allowSuspendConnect) {
long timeout = session.calculateTimeout(getTimeout());
// Support old clients that do not send advice:{timeout:0} on the first connect
if (timeout > 0 && wasConnected && session.isConnected()) {
// Suspend and wait for messages
Continuation continuation = ContinuationSupport.getContinuation(request);
continuation.setTimeout(timeout);
continuation.suspend(response);
scheduler = new LongPollScheduler(session, continuation, reply, browserId);
session.setScheduler(scheduler);
request.setAttribute(LongPollScheduler.ATTRIBUTE, scheduler);
reply = null;
metaConnectSuspended(request, session, timeout);
} else {
decBrowserId(browserId);
}
} else {
// There are multiple sessions from the same browser
Map<String, Object> advice = reply.getAdvice(true);
if (browserId != null)
advice.put("multiple-clients", true);
if (_multiSessionInterval > 0) {
advice.put(Message.RECONNECT_FIELD, Message.RECONNECT_RETRY_VALUE);
advice.put(Message.INTERVAL_FIELD, _multiSessionInterval);
} else {
advice.put(Message.RECONNECT_FIELD, Message.RECONNECT_NONE_VALUE);
reply.setSuccessful(false);
}
session.reAdvise();
}
}
} finally {
if (reply != null && session.isConnected())
session.startIntervalTimeout(getInterval());
}
} else {
if (!isMetaConnectDeliveryOnly() && !session.isMetaConnectDeliveryOnly()) {
writer = sendQueue(request, response, session, writer);
}
}
}
// If the reply has not been otherwise handled, send it
if (reply != null) {
if (connect && session != null && !session.isConnected())
reply.getAdvice(true).put(Message.RECONNECT_FIELD, Message.RECONNECT_NONE_VALUE);
reply = getBayeux().extendReply(session, session, reply);
if (reply != null) {
getBayeux().freeze(reply);
writer = send(request, response, writer, reply);
}
}
}
// Disassociate the reply
message.setAssociated(null);
}
if (writer != null)
complete(writer);
} catch (ParseException x) {
handleJSONParseException(request, response, x.getMessage(), x.getCause());
} finally {
// If we started a batch, end it now
if (batch) {
boolean ended = session.endBatch();
// Flush session if not done by the batch, since some browser order <script> requests
if (!ended && isAlwaysFlushingAfterHandle())
session.flush();
} else if (session != null && !connect && isAlwaysFlushingAfterHandle()) {
session.flush();
}
}
} else {
// Get the resumed session
ServerSessionImpl session = scheduler.getSession();
metaConnectResumed(request, session);
PrintWriter writer;
try {
// Send the message queue
writer = sendQueue(request, response, session, null);
} finally {
// We need to start the interval timeout before the connect reply
// otherwise we open up a race condition where the client receives
// the connect reply and sends a new connect request before we start
// the interval timeout, which will be wrong.
// We need to put this into a finally block in case sending the queue
// throws an exception (for example because the client is gone), so that
// we start the interval timeout that is important to sweep the session
if (session.isConnected())
session.startIntervalTimeout(getInterval());
}
// Send the connect reply
ServerMessage.Mutable reply = scheduler.getReply();
if (!session.isConnected())
reply.getAdvice(true).put(Message.RECONNECT_FIELD, Message.RECONNECT_NONE_VALUE);
reply = getBayeux().extendReply(session, session, reply);
if (reply != null) {
getBayeux().freeze(reply);
writer = send(request, response, writer, reply);
}
complete(writer);
}
}
private PrintWriter sendQueue(HttpServletRequest request, HttpServletResponse response, ServerSessionImpl session, PrintWriter writer)
throws IOException {
final List<ServerMessage> queue = session.takeQueue();
for (ServerMessage m : queue)
writer = send(request, response, writer, m);
return writer;
}
@Override
protected ServerMessage.Mutable[] parseMessages(HttpServletRequest request) throws IOException, ParseException {
return super.parseMessages(request.getReader(), true);
}
@Override
protected PrintWriter send(HttpServletRequest request, HttpServletResponse response, PrintWriter writer, ServerMessage message) throws IOException {
StringBuilder builder = new StringBuilder(message.size() * 32);
if (writer == null) {
response.setContentType(_mimeType);
writer = response.getWriter();
}
builder.append("[").append(message.getJSON()).append("]");
writer.append(builder.toString());
return writer;
}
@Override
protected void complete(PrintWriter writer) throws IOException {
}
private class LongPollScheduler implements AbstractServerTransport.OneTimeScheduler, ContinuationListener {
private static final String ATTRIBUTE = "org.cometd.scheduler";
private final ServerSessionImpl _session;
private final Continuation _continuation;
private final ServerMessage.Mutable _reply;
private String _browserId;
public LongPollScheduler(ServerSessionImpl session, Continuation continuation, ServerMessage.Mutable reply, String browserId) {
_session = session;
_continuation = continuation;
_continuation.addContinuationListener(this);
_reply = reply;
_browserId = browserId;
}
public void cancel() {
if (_continuation != null && _continuation.isSuspended() && !_continuation.isExpired()) {
try {
decBrowserId();
((HttpServletResponse) _continuation.getServletResponse()).sendError(HttpServletResponse.SC_REQUEST_TIMEOUT);
} catch (IOException x) {
logger.trace("", x);
}
try {
_continuation.complete();
} catch (Exception x) {
logger.trace("", x);
}
}
}
public void schedule() {
decBrowserId();
_continuation.resume();
}
public ServerSessionImpl getSession() {
return _session;
}
public ServerMessage.Mutable getReply() {
Map<String, Object> advice = _session.takeAdvice();
if (advice != null)
_reply.put(Message.ADVICE_FIELD, advice);
return _reply;
}
public void onComplete(Continuation continuation) {
decBrowserId();
}
public void onTimeout(Continuation continuation) {
_session.setScheduler(null);
}
private void decBrowserId() {
WebSocketTransport.this.decBrowserId(_browserId);
_browserId = null;
}
}
}